The present invention relates to a total synthesis method for preparing an indole structure derivative product class, of the tryptamine type, in particular of melatonine or N-acetyl-5-methoxytriptamine type, having a high purity degree and easily soluble, for therapeutic use against acquired immuno-deficiency syndromes or so-called AIDS.
As is known, it has been found that melatonine (MTL), administered with suitable doses and at given times, is able of reducing proteic synthesis of hypothalamus and hypophisis and that it, moreover, may inhibit the synthesis of gonadostymulines.
Such an action is probably exerted by means of a modulation of genic transcription and repression, as well as on the incretion of the two GH and PRL growth factors, under particular conditions.
The above mentioned overall effects, which are associated with other particular actions, as disclosed in a more detailed way hereinafter, justify as useful, even if not indispensable, the use of melatonine against tumours.
In fact one may reasonably think that melatonine pertains to that class of drugs which interfere with the growth of neoplastic cells and reduce the life time thereof.
On the other hand, also known is the fact that presently available methods for making the tryptamine structure having the hydrogen atom at the 5-position replaced by the group OCH.sub.3, are based on a series of chemical reactions providing 2-carboxyethyl-3-(2-phthalimidoethyl)-5-methoxy-indole, therefrom there is obtained 5-methoxytryptamine by means of a plurality of comparatively complex and low yield processing steps.
More specifically, known prior art methods comprise an alkaline saponifying step providing 2-carboxy-3-(2-O-carboxybenzamidoethyl)-5-methoxy-indole acid which is then dry decarboxylated at 250.degree. C. in order to form phthalimidoethyl-5-methoxy-indole, which is then water hydrazinolized to provide 5-methoxytryptamine.
In order to obtain pure N-acetyl-5-methoxytryptamine or melatonine with a high yield, it is necessary to have a high purity starting product, that is 5-methoxytryptamine.
Known conventional purifying methods, based on the use of solvents or mixtures thereof, on the other hand, have not provided a sufficiently high purity degree with a contemporaneous high production yield.